In power tool apparatus generally of the nature requiring bevel angle changes, there is the need to locate the operating tool, such as a saw blade, at various angles relative to the horizontal. Typically, this is accomplished by a worm-screw arrangement. For large incremental angle changes, a considerable amount of time is required to set the tool.
In a co-pending application assigned to the present assignee, there is disclosed a power tool apparatus which employs a rapid set lever operated arrangement for positioning the operating tool at desired bevel angles. The serial number for this application is U.S. Ser. No. 31,271 filed Apr. 18, 1979. In circumstances where the weight of the assembly to be pivoted is relatively small, or where the components are mounted physically close to the pivot point, the operator of such equipment generally can move or pivot it through the required bevel angle unassisted by any mechanical leverage scheme. However, for equipment whose purpose is to perform heavy duty work, the pivoted assembly including the motor, operating tool and supporting frame may run as much as forty (40) pounds. Further, because of the component sizes, they must be displaced a relatively large distance from the pivot point. It is therefore impractical and undesirable to move the assembly to the various bevel angles without some form of mechanical advantage or assistance. Heretofore, as noted above, this was accomplished by a worm-screw arrangement which provided the operator with a significant mechanical advantage, but, as noted, resulted in a slow setting of the bevel angle.
It is therefore a primary object of this invention to provide means for assisting the operator in rapidly setting the bevel angle for heavy duty power apparatus such as a table saw.
It is a further object of this invention to provide means for holding the bevel angle position achieved without the need of the operator exerting a holding force.
It is still another object of this invention to provide a means which assists the operator in "holding" the pivoted assembly when returning the tool to a smaller angle setting.
It is yet another object of the invention to provide an operator assist means for setting and resetting the bevel angle which still results in the operator retaining a "feel" as he positions the assembly.